RM0033 Rev 9 913/1381
RM0033 Ethernet (ETH): media access control (MAC) with DMA controller
956
The most significant bit determines the register to be used (hash table high/hash table low),
and the other 5 bits determine which bit within the register. A hash value of 0b0 0000 selects
bit 0 in the selected register, and a value of 0b1 1111 selects bit 31 in the selected register.
For example, if the DA of the incoming frame is received as 0x1F52 419C B6AF (0x1F is the
first byte received on the MII interface), then the internally calculated 6-bit Hash value is
0x2C and the HTH register bit[12] is checked for filtering. If the DA of the incoming frame is
received as 0xA00A 9800 0045, then the calculated 6-bit Hash value is 0x07 and the HTL
register bit[7] is checked for filtering.
If the corresponding bit value in the register is 1, the frame is accepted. Otherwise, it is
rejected. If the PAM (pass all multicast) bit is set in the ETH_MACFFR register, then all
multicast frames are accepted regardless of the multicast hash values.
The Hash table high register contains the higher 32 bits of the multicast Hash table.
Ethernet MAC hash table low register (ETH_MACHTLR)
Address offset: 0x000C
Reset value: 0x0000 0000
The Hash table low register contains the lower 32 bits of the multi-cast Hash table.
Ethernet MAC MII address register (ETH_MACMIIAR)
Address offset: 0x0010
Reset value: 0x0000 0000
The MII address register controls the management cycles to the external PHY through the
management interface.
313029282726252423222120191817161514131211109876543210
HTH
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:0 HTH: Hash table high
This field contains the upper 32 bits of Hash table.
313029282726252423222120191817161514131211109876543210
HTL
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bits 31:0 HTL: Hash table low
This field contains the lower 32 bits of the Hash table.
3130292827262524232221201918171615141312111098765432 1 0
Reserved
PA MR
Reserved
CR MW MB
rw rw rw rw rw rw rw rw rw rw rw rw rw rw
rc_
w1
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